Why Water is our responsibility
It is simple – life depends on water.
66% of the world’s surface is covered by 1,370x1,012m³ of water, but 97.5% of this is brackish salt water. Of the 2.5% of freshwater (342.5x1,012m³), the biggest part is frozen as snow or ice. This leaves less than 50% or about 171.25x1,012m³ that is accessible for consumption in the form of ground water, inland lakes (0.4%), and flowing rivers (30.1-48.7%). (source)
Earth may be called the blue planet, but fresh water is a finite resource. The world’s population is growing fast and water use is growing even faster. About 1 billion people lack access to fresh water and about 5 million people die each year from diseases caused by poor drinking water or poor sanitation often resulting from a water shortage. (source)
Water consumption – Water footprint
The water footprint tells how much demand a product places on (fresh) water resources. It was developed to give a sense of how much water is consumed and polluted in the processing stages for the production of goods. It is measured in cubic meters of water per ton of goods produced, or liters per kilogram.
There are three impacts on water. (source: “WFN (2017) Guiding farmers toward sustainable cotton production – Managing the water footprint on cotton farms. Training materials for farmer engagement. C&A Foundation” see)
Green water footprint:
Volume of rainwater evaporated or incorporated into the product
Blue water footprint:
Volume of surface- or groundwater evaporated or incorporated into a product, lost return flows into the water system
Grey water footprint:
Volume of water needed to meet water quality standards
After food retail/agriculture, the textile industry consumes the greatest amount of water per one Euro turnover. (source) Clearly – the textile industry has a significant responsibility here.
Water stewardship and risk regions
While the water footprint offers an easy, understandable orientation, it neglects some main facts:
- Globally speaking, the water quality varies widely
- Additionally, fresh water is unevenly distributed and used on the globe
- Water is a fundamental right for each individual and for the human community/society, only secondary it is an economic good
Water stewardship assumes an enlarged perspective. It is about companies understanding the risks that are faced from water scarcity and pollution, while taking action to help ensuring that water is managed sustainably as a shared, public resource. Stewardship goes beyond the efficient use of water. It is also about the private sector collaborating to protect shared freshwater resources with governments, businesses, NGOs, communities, and so on. In other words: The main goal should not only be to reduce water by the industry regionally, but to make fresh water accessible to people (and animals) around the world.
The water footprint within a local context
The majority of Europe (except e.g. Spain) does not lack fresh water. This cannot be said about huge parts of North Africa, India or China (source) which do suffer from the shortage of fresh water, sometimes as a result of pollution. This fact leads to the next aspect: The total consumption of water is important, but it is even more important to view consumption within the regional context (water quality, water shortages, regulation, perceptions/image of water). Rinsing cotton with fresh water – a high-water consuming process – in regions with few water resources while the local people die of thirst is a questionable practice – whereas rinsing it with only natural rainwater might already be a better solution.
But, there are other, less water-demanding options and alternatives like using hemp or man-made fibres. While having a look at the different factors, this should be kept in mind, as sourcing does have a significant impact on water.
Natural vegan fibres: Cotton & hemp
Natural vegan fibres like cotton or hemp require water to grow, but the needed amount varies tremendously. Cotton (along with sugar and rice) is notorious as one of the thirstiest plants on earth. The UNESCO Water Footprint for Cotton Consumption reports that cotton consumption is responsible for 2.6% of the global water. (source)
The global average water footprint of different plant fibres, 1996-2005 by Mekonnen and Hoekstra (2011a) gives the following overview:
It shows, cotton requires in total 9,114l per kg whereas hemp needs only a third of it. The source of water for hemp is simply rainwater (green), but rain is not sufficient for conventional cotton. It needs 2,955l of irrigation water. Moreover, 9,96l (grey) water is needed to dilute pollution from fertilizers and pesticides that are needed for cotton – compared to 693l water for hemp. Generally, it is said that cotton takes up 16% of the insecticides and 7% of the pesticides used worldwide (source). All numbers above are listed in the impressive chart by Mekonnen and Hoekstra (2010) (source).
Additionally to the approximately 10,000l water used for growing cotton crop, cotton requires 30l/kg for bleaching, 140 l/kg for dyeing, 190 l/kg for printing and 140 l/kg for finishing – Chapagain and colleagues (2005). More about dyeing in the next chapter.
Attention: The word “average” is important. The used chart shows figures for almost each country - which vary widely! Therefore, not only the water footprint itself should be considered, but also regional footprint together with the water stewardship approach. Only in combination it is possible to judge the sustainability of a particular material from a region. The Sustainable Apparel Coalition seems to think similar and has already started to include more aspects of the water stewardship in the HIGG INDEX (source).
Natural vegan fibres: Organic Cotton
In 2016 a total amount of 107,980mt organic cotton has been produced globally (source). There are 18 countries producing cotton. The biggest ones are India, China and the USA – see WFN (2017) Guiding farmers toward sustainable cotton production – Managing the water footprint on cotton farms. C&A Foundation.
Unfortunately, organic cotton is not listed in the same water footprint source that was used for conventional cotton and hemp earlier. The information provided by Water Footprint and Textile Exchange about the water consumption of organic cotton – found in other documents – differs. The author believes that the figures are different due to the varying crops and agricultural regions and that therefore a generalization is dangerous. Nonetheless it can be said: The idea of organic cotton is not to use genetic engineering, chemical pesticides or fertilizers which have a big impact on (grey) water and to use less fresh (blue) water to spare potential drinking water. Both ideas seem generally helpful, but should be verified by comparable figures at first.
Natural fibres: Wool
A sheep is thirsty and hungry, so wool requires water. One sheep gives circa 3,5-4kg wool per annual shear (and 35-45kg meat if slaughtered). 3 Mekonnen & Hoekstra (2012)’s waterfootprint calculates (source),288l per kg of sheep skin with wool stems (source). In the given figure, it is unclear over how many years this water was consumed. Depending on the years/age of the sheep, the number might vary as a sheep can be sheared annually.
Additionally, it should be taken into consideration how much water is needed for the wool as there are also leather and meat as byproducts. And it is always important to look where sheep farming takes place. Grazing sheep in the mountains, where nothing else can be cultivated and who drink water that is coming mainly from rivers and lakes, is a best case scenario.
Man-made fibres based on petrol
Polyester filament yarns have a water footprint of maximum 71,033l water per kilogram and polyester staple fibres 71,409l/kg, but only 52l (blue) water is needed for the production of the filament yarn respectively 32l for the staple fibre. “The blue water footprint for polyester primarily occurs during the fibre manufacturing stages, whilst the grey water footprint comes from all production phases with the oil exploration and refinery phases contributing the largest share” – “Water footprint assessment of polyester and viscose and comparison to cotton. Supported by C&A Foundation”.
Man-made fibres based on Cellulose
With 66%, China was the world's largest viscose fibre producer in 2015 – WFN (2017) Viscose fibres production: An assessment of sustainability issues, Water Footprint Network, The Hague”. However, the following numbers are based on wood from plantations in Brazil. Viscose staple fibres have a total water footprint of 6.78l, viscose filament yarn from batch washing is 3,305l and viscose filament yarn from continuous washing is 30,596l/kg. The part of rainwater (green) is at a constant of 33l whereas the amount of additional (blue) water rinsing varies. The biggest amount in water footprint is the ‘grey’ one. It is 4,89l for viscose staple fibres, 3,192l for viscose filament yarn from batch washing and 30,192l for viscose filament yarn from continuous washing – “Water footprint assessment of polyester and viscose and comparison to cotton (Supported by C&A Foundation)”. The cellulose based fibre lyocell by Lenzing (booth P05+ P06) is not only using a non-toxic solvent, but is moreover re-using the solvent and process water in a closed loop process. This shows that not only the planting, but also the fibre production is important to take into consideration to assess the water footprint.
Recycled and recyclable content
Mono-fibre (100%) based materials are recyclable whereas fibre blends can’t be recycled that easily yet. Recycling material is a way to avoid waste and to maintain precious resources. Depending on the material and how it is recycled, less water is needed than for the virgin material. Chemical recycling of polyester with e.g. glycol needs only 8,5% of the water that is needed for its virgin equivalent according to Perpetual. Recycled PES is most often coming from PET-bottles that are sorted by color, cleaned and spun into yarn. Important to know: Bottles for carbonic acid content like sparkling water or coke, need a special treatment that exclude them from recycling. Moreover, only transparent bottles can be dyed. Green or blue bottle will keep the color. What looks first of all as an disadvantage can be an ecological and financial advantage: Without any new dyeing (and any additional cost), the yarn is blue or green and gives color to the new garment. Also cotton, wool or other man-made fibres use this coloring approach. Of course, it is fraudulent labeling if the “recycled” bottle has never been in use nor seen any liquid.
Bringing back the production waste into production, optimizes the production process and can be considered (pre-consumer/post-industrial) recycling. Giving post- consumer waste a new life is the aspect of recycling which will become even more important in the future as otherwise this waste would end in a landfill or in the ocean. SEAQUAL (booth H12) is exactly doing this: Collecting plastic waste from the Mediterranean Sea in the area of Spain in order to recycle it into yarn and fabrics. According to SEAQUAL, 20% less water is needed for their recycled PES compared to virgin polyester.
Textile production using less water
Water is important in textile production. How much water is needed mainly depends on factors such as the raw material used, the pretreatment dyeing, and the finishing processes.
Some processes are the same for the production of every textile:
- Plants as cotton or hemp – so natural fibres – need water. Wood that is used for cellulose fibres is consuming water, too.
- Whether natural or man-made, textiles need to be pretreated (e.g. bleached) before being dyed to achieve a good color result. Special finishes as HeiQ Dyefast (booth P07+ E05) can also help to reduce the amount of water required during pretreatment (source).
- Mainly knitted textiles (woven only partly) need to be washed because residues from the knitting process like oils, waxes and silicone preparations need to be rinsed out. But generally fabrics at this stage can only profit by cleaning for a better color result in the next step: Dyeing. The wastewater in C. can concentrate huge amounts of chemicals.
While the term “water-free” or “dyed without water” might be true for the following dyeing technologies, water is still needed for the entire textile manufacturing process. According to the World Bank, as much as 20% of the water pollution can be traced back to the coloring and finishing of textiles (source).
The following texts give an overview about dyeing (normally circa 50-450 l water/kg) see “Water Footprint Assessment of washing-dyeing-finishing mills in China & Bangladesh” – of course, good fastnesses still need to be confirmed for each color individually by the producer.
Less water during Dyeing
Post-Weaving/Knittig: Piece dyed
Approximately 1,200-2,400l of water for the dyeing and around 1,200-2,400l of water for the rinsing process is consumed in conventional dyeing methods, for example, for 2,000 yards (300kg) of polyester fabric with a liquor ratio between 1:6 and 1:12. The dyestuff is added to machinery during the process and penetrates into the fabric with water, textile auxiliaries and under pressure. The amount of dye and water depends on the type of fibre, fabric, depth of shade, weight as well as the machinery and the end use of the product. At the end of the process, the wastewater has to be drained off from the dyeing machinery. The dyestuff used in the process is directly passed into the wastewater treatment system. If a dyehouse is using economical dyestuffs that are more effective and exhaust at a very high level, the water treatment would be easier as well as more economical for the dyehouse. In most cases, production sites drain the water into their wastewater and bring the water to a safe level of aftertreatment. Unfortunately, the pollutants like salt, solidified dyestuff and auxiliaries still need to be flocculated out from the wastewater. After that a purification process needs to be done. Currently, it has not been proven if it is more sustainable (in terms of water and energy) to have a closed water circle exclusively for the production site or a wastewater treatment for industry mixed with a household water system.
Note: Dyeing can be carried out in a batch-dyeing or in a continuous dyeing process. If a closed machine is loaded with a certain amount of material/yarn/fabric it is called batch- or discontinuous-dyeing. Continuous dyeing refers to a method that uses open machinery through which the material/yarn/fabric is continuously pulled to apply the additives or chemicals and typically consists of dye application, dye fixation with heat and/or chemicals and a subsequent washing process followed by the drying.
In the conventional process, the yarn or fabric is first produced and then dyed. Other dyeing methods require less water (circa 75-90% less water can be seen as benchmark). These other methods are discussed below:
Pre-Weaving/Knittig: Yarn dyed
In piece-dyeing the piece, so the fabric or garment, is dyed, while in yarn-dyeing the yarn cone/spun or the yarn package is dyed.
Color can already be melted into man-made polymer fibres during the yarn production long before they are woven or knitted. While man-made fibre yarns like polyester, polyamide, polypropylene or viscose/rayon are still in liquid form, the dyestuff and/or pigment) is added before pressing through an extruder/spinarette that determines the cross-section. Famous brands like e.dye (booth F11) and We aRe SpinDye® (booth P03) use this method. The method is not applicable for natural fibres, as they are already harvested as solids from their source. They remain to be colored differently (piece-dyeing or printed).
PRE-WEAVING/KNITTING: SOLUTION-, DOPE & SPUN-DYED
During dyeing methods as spin-dyeing, it might be necessary to work with solution or dope. As the names imply, a solution or dope is required in the dying process. Both result in fibres that are fully impregnated in a one-step process. The solution or dope activates the color to connect with the fibre. Spun-dye refers to natural colors and dyestuff being implemented by an ultrasonic process before the yarn is spun. It is mostly used for natural fibres like cotton, tencel etc.
PRE-WEAVING/KNITTING: SOLUTION-DYED CHROMUCH
The producer determines whether pigment, solvent dyes/liquid colorant/dyestuff or some combination is used. Pigments do offer excellent color fastness results above grade 4, under temperatures of 190°C, but the colors might often be dull and the range of pigments is limited. Other types of dyestuff often experience color migration problems, especially under heat although the color palette is wide and the colors are brilliant.
Nan Ya Plastic (booth B10) decided to use solution-dyeing with both pigments and dyestuffs in their product called Chromuch. The migration problem is solved and most of the neon (brilliant and deep) colors can be achieved with excellent color fastness according to Nan Ya Plastic.
PRE- & POST-WEAVING/KNITTING: DyeCoo
Dyecoo has developed a process that uses hypercritical (or supercritical) CO2 instead of liquid water as in the conventional process. The technology is restricted to polyester and disperse dyes as well as works on the basis of pigments and can be applied to the yarn (pre-weaving/knitting) or to the fabric (post-weaving/knitting)
The color is impregnated directly with water or steam (so even less water) depending on the printing machine and the used dyestuff. Normally the ink is liquid, but there are also technologies using ink powder (InkPresso) that is liquefied by the print machine during production. The huge advantage of digital printing in general: It does not need any minimum quantities – exactly the required quantity can be produced (instead of a minimum quantity).
The technology has improved in recent years becoming less expensive and faster – printing can be a real option to consume less water, produce less waste, and reduce costs.
Similar to printing, the dye stuff is applied to the surface of the fabric. Spray-dyeing is not meant to produce uni-colored fabrics, but effects and colorful eyecatchers. The color is sprayed as a liquid (so with little water content) and does not require the addition of water as needed in piece-dyeing. Therefore, it can be considered as a low water consumption process.
Washing – the water footprint Part II
The water footprint does not end with the production of a garment. Some refer to washing as the internal water footprint. A single laundering cycle requires approximately 45-60l (for probably 7-8kg of garments) (source). Depending on the fibre, the water footprint for household washing versus the water footprint for fabric production including dyeing can be either a small or a large percentage. As part of the 11,000l to produce a cotton t-shirt, 60l for washing (blue water footprint) is not that much, but 60l to wash a 250g t-shirt of the 750l used to produce (hemp is 3,000l/1kg) is quite a bit. Suddenly, 8% for a single wash load (with only one piece) after being worn only a few times seems incredible. And, although the washing frequency is an individual decision made by the consumer because of dirt, bad odor, hygienic reasons or simply the psychological habit of washing clothes after (just one) use, the internal water footprint is often excessive. According to Polygiene, up to 54% of the water use occurs during consumer use. 1 But bad odor - the result of bacteria eating the sweat – can be easily minimized by special treatments that are implemented in the yarn, fabric or garment surface. Polygiene (booth K14) uses a technology based on silver salts, other producers use minerals or menthol.
Simply put: Plastic pieces smaller than 5mm in diameter (source) are called microplastics. Where microplastics come from and how to prevent microplastics is a complicated topic. The larger microplastics probably have their origin in plastic that has been shredded into smaller pieces by friction or polymer modification.
For example: huge areas of waste, containing plastic bottles and PET bags, rub against each other or against corals. This and other factors like solar UV radiation break them into small parts, so that the oceans currents transport them away from “civilisation” and into the natural environment. Moreover, rubber tires undergo a similar process and are suspected to be a major source of pollution, too. Tires rub against the road from where wind and rain transports these microplastics into the soil, rivers, lakes and the marine waters.
Fibres, fabrics, and garments lose microscopical small particles during wearing and washing. Those particles can be of natural or man-made origin, that is cotton, hemp, wool or polyamide and polyester based on petrol or on cellulose. The effect of microplastics in general and plastic with textile origin in particular, is currently the subject of many discussions and studies. The federal German Environmental Agency states that up to 2,000 pieces of man-made fibres are discharged into marine waters via laundering and the watering of plants.4 TU Dresden claims that 5-20% of the original garment weight is lost during wearing and washing.
Reducing microplastics with textile origin
TextileMission – Initiative Against Microplastics is a collaborative project that is currently researching how microplastics can be avoided, reduced, re-used, and destroyed. University of Applied Sciences - Hochschule Niederrhein and other research institutes and industry partners are following several approaches. 1 In particular, Hochschule Niederrhein investigates the actual particle discharge during household washing by filtration of the total amount of wastewater including detergent.
Strategies that might help
- Ensure the use of more sustainable materials. That might mean:
– Use materials that last longer
– Use materials that can be recycled (closing the loop of a life cycle) (source)
- Develop materials that deliver the same performance but require less resources. A fabric of the same material that is lighter, but keeps you as warm as the heavier version can also reduce the ecological footprint.
- Construct yarns that have less/no fibre-loss brushed fabrics and fleeces are suspected
to lose more fibres than un-brushed ones. Therefore Pontetorto (booth J16+J17) has
replaced those potentially water-polluting fibres by biodegradable ones). POLARTEC (booth K05) follows the approach to minimize shedding.
- Develop fibres that are biodegradable, not only in industrial composting plants, but also under environmental conditions.
IMPORTANT: Biodegradation should not mean fragmentation into microplastics (=oxo-degradation), BUT biodegradation into water, CO2, methane, and biomass/minerals ONLY (source). PRIMALOFT (booth G11) for example, states to have developed an insulation that is made of 100% recycled materials and degrades to water, methane, carbon dioxide and biomass only (marine environment testings are in progress).
- Optimize household washing: Less frequent washing – avoid toploader washing machines – wash only if the drum is full, as a half empty machine leads to more friction between the clothes and the wash drum creating more fibre-loss while the amount of water remains the same.
- Reduce fibre-release during consumer phase – especially during washing (e.g. use washing machines that are able to filter microparticles). In how far fibre-catching balls or nets are helpful to reduce the microfibre emission is still being tested.
- Avoid that sewage sludge is used as fertilizer in agriculture and microplastics thereby
return into the water supplies. Thermo-recycling/burning of the sewage sludge could help.
- Support initiatives to clean the environment from waste.
A special Thank you for the support to:
- The PERFORMANCE DAYS exhibitors
- Hochschule Niederrhein
- Water Footprint Network
- Anna Rodewald
- Detlef Fischer